Dielectric spectroscopy of biological cells in microfluidic devices

Abstract

This work is focused in the area of ligand-receptor interaction analysis, working with a well-characterized biological model (ligand: lactoferrin, receptors: nucleolin and sulfated proteoglycans). The purpose is to be able to assign, in real time, a specific crossing pathway to a ligand/receptor pair, without the use of molecular labels. The classification is based on changes in the electrical properties of the cells. We propose to follow the various phases of assembly between the ligand and receptors present or not on a set of mutant CHO cell lines, and internalization of the ligands/receptors complexes into the cells. Various BioMEMS have been designed and fabricated in order to characterize the variation of the electrical properties of the biological cells. We are interested in both dielectric (i.e. polarization) and vibrationnal (i.e. absorption) spectroscopy. Several devices are currently tested for low (<10MHz) and high (>40GHz) frequency range (LFR & HFR) measurements. In the LFR, we have fabricated coplanar and 3D electrodes sensors for impedance measurements. In the HFR, we have designed and processed coplanar waveguides. We have also tested various methods for the immobilization of the cells (i.e.: mechanical, chemical and electrical). In the LFR, we have performed static and dynamic measurements on small cluster of cells. In the HFR, we have shown that we can propagate microwaves along submicrometer single wires (Goubau propagation). We are going to use these HFR devices for measurement on small cluster of cells. This work is carried out within the FENOTIP project funded by the French Research National Agency (ANR) as PNANO no05-0244-A3. © Springer-Verlag 2007.